Image Processing Toolbox User's Guide Previous page   Next Page

Adjusting the Contrast and Brightness of an Image

To adjust the contrast or brightness of an image displayed in the Image Tool, use the Adjust Contrast tool. The Adjust Contrast tool provides an interactive way to adjust the contrast and brightness of an image by manipulating the display range of the image.

The Adjust Contrast tool displays a histogram of the image that is overlaid with a red rectangular box, called a window. The histogram represents the dynamic range of the image, i.e., the full grayscale resolution possible given the image storage class. The window represents the display range of the image, i.e., the actual range of pixel values in the image. An image where grayscale values in the display range do not take full advantage of the dynamic range has a dull, washed-out, low-contrast look. By changing the size of the window, you can make the display range take better advantage of the full dynamic range of the image. The Adjust Contrast tool also provides a way to adjust contrast and brightness using the mouse -- see Using the Window/Level Tool.

For example, view an image in the Image Tool.

Start the Adjust Contrast tool by clicking the Adjust Contrast button in the Image Tool toolbar, or by selecting the Adjust Contrast option from the Tools menu in the Image Tool.

The following figure shows the Image Tool with the Adjust Contrast tool. For more information, see these additional topics:

Image Tool with Adjust Contrast Tool

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